Fluid-electro transducer



)(R l q fi gfi 'i Jflm 1966 H. B. HORTON 3,258,685

FLUID-ELECTED TRANSDUCER Filed April 22, 1963 52- 54 4a 44 4e 54 5o 36POWER STREAM VOLTAGE SOURCE FIG. 2b 64 INVENTOR 0 HAROLD B. HORTON BY WMM A TTORNEYS 5,258,685 FLUlD-ELECTRO TRANSDUCER Harold B. Horton, NewCanaan, Conn., assignor to Sperry Rand Corporation, New York, N.Y., acorporation of Delaware Filed Apr. 22, 1963, Ser. No. 274,667 12 Claims.(Cl. 324-44) The present invention relates to a novel fluid-electrotransducer device, and more particularly, to one wherein fluid flow in achannel may be converted into an electrical manifestation by theelectrical charging of moving fluid particles.

The invention herein disclosed finds novel and particular, although notexclusive, use in the field of pure fluid amplifiers. These amplifiersare a comparatively recent addition to the data processing and controlsystem arts. The amplifiers are small, rugged, and inexpensive. They maybe constructed of plastic, metal, or ceramic material, and basicallycomprise a plurality of interconnected fluid conduits. For furtherinformation concerning the characteristics and mode of operation of purefluid amplifiers, reference should be made to the publications entitledScience and Mechanics," June 1960, and System Design, April 1960. Asexplained in the aforementioned publications, a pure fluid amplifier isresponsive to fluid control signals of relatively low energy forproducing fluid output power signals of relatively high energy. Forcertain environments it may be desirable to directly convert the outputpower signal of a pure fluid amplifier into an electrical manifestation.This invention provides means for accomplishing this result without theinclusion of any moving parts.

Therefore, an object of the present invention is to provide a transducerwhich permits conversion of a fluid signal directly into an electricalsignal without moving parts.

Another object of the present invention is to provide means forconverting the output of a pure fluid amplifier into an electricalsignal.

Yet another object of the present invention is to permit the conversionof fluid signals into electrical signals United States Patent by firstcharging moving fluid particles, then directing said particles throughmagnetic or electrical field detecting means whereby electrical signalsar induced therein.

Further objects of the present invention will become apparent during thecourse of the following description which is to be read in view of thdrawings, in which:

FIGURE 1 shows a bistable pure fluid amplifier with magnetic outputtransducer means;

FIGURES 2A and 2B show a proportional pure fluid amplifier with magneticoutput transducer means; and

FIGURE 3 shows a modification of the invention whereby electrostaticoutput transducer means are provided.

Referring first to FIGURE 1, there is shown a bistable pure fluidamplifier generally indicated by reference numeral'lo whose output fluidsignal is directly converted into an electrical manifestation bymagnetic means. This fluid amplifier comprises a substantially tubularbody having an input duct 12, and right and left output ducts 14 and 16,respectively. A fluid source, such as a compressor (not shown),continuously supplies a power stream fluid such as air or other gas, ora liquid, to input duct 12 from whence it passes through a constrictedorifice or nozzle 18 into an interaction chamber 20. In order to deflectthe power stream into either output channel 14 or output channel 16,control fluid streams may be selectively applied to interaction chamber20 via conduits 22 and 24 from sources not shown in FIGURE 1.

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As is well known in the pure fluid art, a power stream of relativelylarge energy may be physically deflected without losing its integrity bymeans of a control stream of lesser energy impinging thereon atsubstantially a right angle. Thus, if control stream fluid is applied toconduit 24 so that it issues into interaction chamber 20 via nozzle 26,the power jet stream issuing from nozzle 18 is deflected into. outputchannel 14. On the other hand, if control stream fluid is introducedinto duct 22 from whence it issues from nozzle 28, the power stream willinstead be deflected into output channel 16. In order to provide abistable characteristic, i.e., a characteristic whereby the power streamremains in the output channel to which it is deflected even aftertermination of the deflecting control stream, the amplifier isconstructed to exhibit the well known boundary layer effect which causesthe power stream to lock onto the outer wall of an output channel towhich it is deflected. This phenomenon is due to the entrainment ofmolecules in the region between said outer wall and said power stream soas to lower the pressure therein. Consequently, once the power stream iscompletely deflected into either output channel 14 or 16 by a controlstream, said control stream may be subsequently terminated withoutcausing the power stream to swing back toward the center of chamber 20.In observing an output channel, therefore, there are only two fluidstates existing therein depending upon whether the power stream is or isnot flowing therethrough. By oflsetting the outer walls of chamber 20from nozzle 18, as indicated by regions 30 and 32, the boundary layerelfect can be enhanced.

The description so far relates to a pure fluid bistable amplifier wellknown in the prior art and with which the present invention isparticularly adapted for use. In many environments the fluid outputsignal from such an amplifier must be converted into an electricalsignal for operating related circuits. This function is performed in anovel manner for components now to be described. Disposed within inputduct 12 is a grid-like structure 34 which is connected by leads 36 and38 to a source of ionizing potential 40 for generating a coronadischarge.

in the duct in the manner of electrostatic precipitation of dustparticles. Grid 34 comprises a network of wires or filaments arranged ina manner to offer minimum resistance to power stream flow therein, butat the same time to provide a plurality of parallel channels throughwhich the power stream fluid passes. As the fluid particles pass throughthe grid, they are given an electric charge which may be either negativeor positive depending upon the polarity of the ionizing voltage. Thegrid is selectively given either a negative or positive charge and theparticles or molecules contacting the grid assume the same charge as thegrid. The charging of fluid particles in this manner is illustrated inCanadian Patent No. 538,851. The actual molecules of the fluid can beionized, or alternatively, the power stream fluid may carry particles ofa different substance which are in turn charged by exposure to thecorona discharge. Other means for charging particles may be used, as byfrictional contact or the like. For the purpose of this explanation, itwill be assumed that the charge so given is negative.

Disposed in proximity with at least one of the output channels is atransducer for detecting the passage of charged particles therethrough.In FIGURE 1, this transducer takes the form of means for detecting themagnetic field set up by the motion of charged particles in the outputchannel. As is well known in the study of electricity, a current ofmoving charged particles such as electrons generates a magnetic fieldwhich is concentric about the axis of particle flow. In FIGURE 1,channels l4 and 16 have arranged thereabout magnetic core material 42and 44, respectively, in a shape of a toroid. Each toroid provides a lowreluctance path for the flux lines of the magnetic field set up aroundthe output channel due to the pasage of charged particles therethrough.These flux lines have a direction around the output channel such thatthey enter the plane of FIGURE 1 and emerge therefrom on the right andleft sides, respectively, of said output channel. Coils 46 and 48 arewound about cores 42 and 44, respectively, in each of which is induced avoltage pulse whenever there is a change in magnitude of this magneticfield at the time that power stream flow in an output channel isinterrupted or initiated. The polarity of the induced voltage in coils46 and 48 is used to set or clear electronic circuits such as flip-flops50 and 52, respectively, in order that they can indicate the presence orabsence of power stream flow in the respective associated outputchannel. A coupling capacitor 54 and 56 can be used to differentiate theinduced voltage pulse from the coil in order to provide a sharptriggering spike to the input of the associated flip-flop.

The operation of FIGURE 1 will now be described. Assume initially thatpower stream flow is locked in output channel 14 only, and thatflip-flop 50 is in its set condition so that a potential'of some valueappears on its output lead 56 to indicate that the power stream takesthis path of flow. Flip-flop 52 is further assumed to be in its clearcondition so that a potential of different value appears on its output58 indictaing no power stream flow in output channel 16. If now controlstream fluid is temporarily'introdnced into duct 22, the power streamissuing from nozzle 18 is deflected into output channel 16 and away fromoutput channel 14. The termination of flow in output channel 14 causesthe disappearance of the magnetic field in core 42. The consequentchange in flux lines linking coil 46 thereby induces therein a temporaryvoltage pulse of some particular polarity which in turn is transmittedvia capacitor 54 to clear flip-flop 50, thus indicating that there is nolonger power stream flow in channel 14. The initiation of power streamflow in channel 16 causes the creation of a magnetic field in core 44,so that a temporary voltage pulse of opposite polarity is induced incoil 48 which thereupon sets flip-flop 52. Flip-flop 52 when setproduces a potential on output lead 58 indicating that power stream flowhas been initiated in channel 16. The control stream in duct 22 can nowbe terminated without the power stream switching back into channel 14.

If a control stream is now applied to duct 24, the power stream switchesback into output channel 14. This immediately establishes a magneticfield in core 42 which consequently induces a temporary voltage pulse incoil 46 of polarity opposite from that induced therein during theoperation previously described above. This voltage is transmitted to setflip-flop 50, thus indicating power stream flow in output channel 14. Inchannel 16, the disappearace of power stream flow therein induces avoltage pulse in coil 48 which is of opposite polarity from that used toset flip-flop 52. This voltage pulse clears flip-flop 52, which is takento indicate the absence of power stream flow in output channel 16.

It will be noted from'the above that the magnetic transducer of FIGURE 1only indicates that a change has occurred in the power stream flowcondition within the respective output channel, but does not specify themagnitude of power stream flow therein. The latter function is notnecessary inasmuch as pure fluid amplifier is bistable and has only twopossible outputs each of predetermined magnitude, according to whetherthe power stream flows or does not flow through an output channel.However, pure fluid amplifiers of the proportional type are quite commonin which the power stream divides between the two output channelsaccording to the particular energy of control stream input. Such a fluidamplifier is shown in FIGURE, 2A and is quite similar to that of FIGUREI. like parts in FIGURES l and 2A are indicated by like referencenumerals in order to avoid the need for a detailed description of theFIGURE 2A amplifier. In FIGURE 2A, however, the degree of power streamdeflection depends upon the value of its impinging control stream, sothat the fluid signal obtained from an output channel is proportional tothe value of control stream input. Hence, there is no bistablecharacteristic in FIGURE 2A. One of the features which makes thispossible is that there is no set back provided downstream from eachcontrol jet, as in the case of FIGURE 1. The output magnetic transducerin this case should be able to determine the amount of power stream flowin an outputchannel, as opposed to mere detection of power stream flowas is only required in FIGURE 1. It is well known the value of themagnetic field is set up about a moving stream of charged particles isproportional to the quantity of charged particles passing a givencrosssectional locaiton per unit time. Consequently, the value of fluxexisting in core 42 or core 44 will depend upon the quantity of powerstream fluid in the associated output channel. Whenever the power streamflow in an output channel is altered, as for example increasing ordecreasing the impinging control stream, then the absolute value of fluxin the core changes accordingly. By providing air gaps 60 and 62 incores 42 and 44, respectively, magnetic flux measuring probes 64 and 66,respectively, can be introduced into the magnetic field. Thisarrangement is best shown in FIGURE 28. Each probe can be respectivelyconnected to magnetic field strength meters 68 and 70 (for example, likeone shown in the US. Patent No. 2,562,120 to Pearson) in order todetermine the absolute magnitude of flux. known means for measuring theabsolute value of flux may also be utilized in the embodiment of FIGURE2A. Therefore, FIGURE 2A is a scheme whereby the absolute magnitude offluid flow in an output conduit can be converted into an electricalmanifestation by charging the fluid flow which in turn sets up amagnetic field whose strength is dependent upon the magnitude of fluidflow.

Electrostatic transducer means may also be provided to detect theelectric field set up by the charged particles in an output conduit.This variation is shown in FIG- URE 3 whereby the output channel 16 (ofamplifier 10 in FIGURE 1) may be provided with a capacitor plate 72instead of magnetic core 44. This plate is external to duct 16 andsurrounds same but is insulated therefrom. The plate is electricallyconnected to a source, such as ground, of positive and negative chargesthrough a dropping resistor 74. The junction between resistor 74 andplate 72 may be connected to an indictaing flip-flop 76 by a couplingcapacitor 78. In operation, the establishment of power stream flow inoutput channel 16 places electrical charges within the interior of duct16 opposite plate 72. These electrical charges (assumed here to benegative), cause a corresponding positive charge to be induced on plate72 in accordance with the well-known principles of electrostatics. Thismeans that electrons leave said plate and travel through resistor 74 toground, thus causing a temporary current to flow through resistor 74which raises the potential of the junction. Said potential is coupled toflip-flop 76 to set same for indicating power stream flow in channel 16.When power stream flow in this channel is terminated, as by thedeflection of the power stream into output channel 14, then electronsare withdrawn from the ground source and sent to plate 72 which causescurrent of the opposite polarity to temporarily fiow in resistor 74.This current temporarily decreases the junction potential which in turnis transmitted to clear flip-flop 76 to indicate absence of power streamflow. A similar electrostatic transducer may be provided in outputchannel 42 for giving complementary signals. Furthermore, well knownmeans for measuring the absolute value of an electric field within Otherwell.

the channel may be employed wherever a proportional fluid amplifier isto be used.

While the preferred embodiments of the present invention have been shownand described, it is obvious that modifications thereto may be made bypersons skilled in the art without departing from the novel principlesas set forth in the appended claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A fiuid-electro transducer which comprises:

(a) a pure fiuid amplifier of the type including an input duct. forreceiving a fluid power stream of moving particles, a plurality ofoutput signal ducts, and at least one fluid control stream input ductfor selectively directing said power stream to said output signal ducts;

(b) first means situated in proximity with said power stream for givingat least some of its said moving particles an electrical charge wherebysaid charged particles generate an electro-magnetic field; and

(c) second means located in proximity with at least one of said outputsignal ducts and situated downstream from said first means, fordetecting the field of charged power stream particles which may beflowing therethrough.

2. The invention according, to claim 1 wherein said second meansincludes a coil positioned so as to be linked by flux of the magneticfield generated by said charged power stream particles.

-3. The invention according to claim 1 wherein said first means ionizesthe fluid molecules of said power stream.

4. A fluid-electro transducer which comprises:

(a) a pure fluid amplifier of the type including an input duct forreceiving a fluid power stream of moving particles, a plurality ofoutput signal ducts, and at least one fluid control stream input forselectively directing said power stream to said output signal ducts;

(b) first means situated within said power stream input duct for givingat least some of said power stream moving particles an electrical chargewhereby said charged particles generate an electro-magnetic field; and

(c) second means loctaed in proximity with at least one of said outputsignal ducts for detecting the field of charged power stream particleswhich may be flowing therethrough.

5. The invention according to claim 4 wherein said first means ionizesthe fluid molecules of said power stream.

6. A fiuid-electro transducer which comprises:

(a) a pure fluid multi-stable amplifier of the type including an inputduct for receiving a fluid power stream of moving particles, a pluralityof output signal ducts, and control steam input ducts for selectivelydirecting said power stream to only one of said output signal ducts at atime;

(b) first means situated in proximity with said power stream for givingat least some of its said moving particles an electrical charge wherebysaid charged particles generate an electro-magnetic field; and

(c) second means located in proximity with at least one of said outputsignal ducts and situated downstream from said first means, fordetecting a change in the field of said power stream as it begins orends its flow therethrough.

7. The invention according to claim 6 wherein said second means includesa coil positioned so as to be linked by flux of the magnetic fieldgenerated by said charged power stream.

8. The invention according to claim 6 wherein said first means issituated within said power stream input duct.

9. The invention according to claim 8 wherein said first means ionizesthe fluid molecules of said 'power stream.

10. The invention according to claim 1 wherein said second meansincludes a capacitor plate positioned so as to detect the electric fieldgenerated by said charged power stream.

11. The invention according to claim 4 wherein said second meansincludes a capacitor plate positioned so as to detect the electric fieldgenerated by said charged power stream.

12. The invention according to claim 6 wherein said second meansincludes a capacitor plate positioned so as to detect the electric fieldgenerated by said charged power stream.

References Cited by the Examiner UNITED STATES PATENTS 1,964,738 7/1934McCreary 3l05 2,004,352 6/ 1935 Simon 310-5 3,080,515 3/1963 Kehoe 310-23,102,224 8/ 1963 Malder 310-11 RICHARD B. WILKINSON, Primary Examiner.

1. A FLUID-ELECTRO TRANSDUCER WHICH COMPRISES: (A) A PURE FLUIDAMPLIFIER OF THE TYPE INCLUDING AN INPUT DUCT FOR RECEIVING A FLUIDPOWER STREAM OF MOVING PARTICLES, A PLURALITY OF OUTPUT SIGNAL DUCT, ANDAT LEAT ONE FLUID CONTROL STREAM INPUT DUCT FOR SELECTIVELY DIRECTINGSAID POWER STREAM TO SAID OUTPUT SIGNAL DUCTS; (B) FIRST MEANS SITUATEDIN PROXIMITY WITH SAID POWER STREAM FOR GIVING AT LEAST SOME OF ITS SAIDMOVING PARTICLES AN ELECTRICAL CHARGE WHEREBY SAID CHARGED PARTICLESGENERATE AN ELECTRO-MAGNETIC FIELD; AND (C) SECOND MEANS LOCATED INPROXIMITY WITH AT LEAST ONE OF SAID OUTPUT SIGNAL DUCTS AND SITUATEDDOWNSTREAM FROM SAID FIRST MEANS, FOR DETECTING THE FIELD OF CHARGEDPOWER STREAM PARTICLES WHICH MAY BE FLOWING THERETHROUGH.